*2.1. Effect of Coatings on the Color Change during Storage*

Color is one of the significant visual characteristics of fresh-cut food items. Excessive discoloration often impacts consumer acceptance, and indicates poor performance packaging techniques used to preserve products [26]. The color change (∆E) value of the samples was used to evaluate discoloration in samples during storage (Figure 1). Change in color was observed in all samples, which was more pronounced in CON (uncoated freshcuts). During the first 12 days of storage, no significant difference was observed in coated samples (Ch, SA + C, and ChCSA). However, at the end of storage, notable differences were observed between all samples. The ∆E values for CON, Ch, SA + C, and ChCSA coated fresh-cuts were 22.90, 16.86, 13.05, and 8.97, respectively, indicating that ChCSA gel coating was more efficient in retaining the color of fresh-cut purple sweet potatoes than their single coatings. Biochemical reactions responsible for the degradation of color pigments in sweet potatoes require oxygen and light [1]. The inner and outer film layers of chitosan and alginate, respectively, form a protective barrier on the surface of the coated fresh cuts, which impacts the selective permeability of gas and light [27,28]. Moreover, Ch

and SA coatings have been reported to improve the storage quality of various fruits by inhibiting color changes such as browning in papaya, apple, and melon [29–31]. fresh cuts, which impacts the selective permeability of gas and light [27,28]. Moreover, Ch and SA coatings have been reported to improve the storage quality of various fruits by inhibiting color changes such as browning in papaya, apple, and melon [29–31].

pigments in sweet potatoes require oxygen and light [1]. The inner and outer film layers of chitosan and alginate, respectively, form a protective barrier on the surface of the coated

*Gels* **2022**, *8*, x FOR PEER REVIEW 3 of 14

**Figure 1.** The effect of single-layer and gel coatings on the changes in total color difference value (ΔE) of fresh-cut purple sweet potatoes. Vertical bars represent means and standard deviation. Bars with different alphabets within the same storage day (lower case) or same treatment group at different storage days (upper case) are significantly different (Tukey's HSD Test, *p ≤* 0.05). **Figure 1.** The effect of single-layer and gel coatings on the changes in total color difference value (∆E) of fresh-cut purple sweet potatoes. Vertical bars represent means and standard deviation. Bars with different alphabets within the same storage day (lower case) or same treatment group at different storage days (upper case) are significantly different (Tukey's HSD Test, *p* ≤ 0.05).

#### *2.2. Effect of Coatings on Weight Loss during Storage 2.2. Effect of Coatings on Weight Loss during Storage*

Fresh-cut products are susceptible to weight loss by transpiration [32]. In addition, excessive weight loss reduces valuation and consumers' perception of purchasing a product [33]. Thus, evaluating weight loss during storage is crucial. Weight loss was gradually increased in all samples according to the storage time (Figure 2). Higher weight loss was recorded in the control samples throughout the storage period, whereas the coated samples had minor weight losses. Significantly, SA + C and ChCSA gel coatings slowed down the weight loss during storage, having the lowest weight loss value (~1.4%) after 16 days of storage. The formation of gel films on the surface of fresh-cut samples improved moisture retention and prevented excess transpiration. Similar to this study, weight loss reduction in coated fresh-cut nectarines [34] and blueberries [24] have been reported. Fresh-cut products are susceptible to weight loss by transpiration [32]. In addition, excessive weight loss reduces valuation and consumers' perception of purchasing a product [33]. Thus, evaluating weight loss during storage is crucial. Weight loss was gradually increased in all samples according to the storage time (Figure 2). Higher weight loss was recorded in the control samples throughout the storage period, whereas the coated samples had minor weight losses. Significantly, SA + C and ChCSA gel coatings slowed down the weight loss during storage, having the lowest weight loss value (~1.4%) after 16 days of storage. The formation of gel films on the surface of fresh-cut samples improved moisture retention and prevented excess transpiration. Similar to this study, weight loss reduction in coated fresh-cut nectarines [34] and blueberries [24] have been reported.
